CN113728167A

CN113728167A - Centrifugal compressor and supercharger

Info

Publication number: CN113728167A
Application number: CN202080031019.6A
Authority: CN
Inventors: 米村淳; 崎坂亮太; 藤原隆; 马场隆弘
Original assignee: IHI Corp
Current assignee: IHI Corp
Priority date: 2019-04-26
Filing date: 2020-03-26
Publication date: 2021-11-30
Anticipated expiration: 2040-03-26
Also published as: US11821432B2; CN113728167B; DE112020002121T5; WO2020217847A1; JPWO2020217847A1; US20220018360A1

Abstract

The centrifugal compressor comprises: an impeller having a main body and a plurality of blades provided on an outer peripheral surface of the main body; an intake passage (130) that faces the impeller in the rotational direction; a throttle mechanism having a throttle member (first throttle member (210)) provided in the intake passage (130), wherein the distance (LL) between the outer peripheral end of the Leading Edge (LE) of the blade and the throttle member is divided by the maximum protrusion height (h) of the throttle member from the inner wall surface of the intake passage (130)_max) And the calculated ratio is 4 or less.

Description

Centrifugal compressor and supercharger

Technical Field

The present disclosure relates to centrifugal compressors and superchargers. The present application claims priority from japanese patent application No. 2019-086357, filed on 26.4.2019, and the contents of which are incorporated herein by reference.

Background

The prior art provides a centrifugal compressor in a supercharger. For example, in a centrifugal compressor provided in a supercharger described in patent document 1, an intake passage is formed upstream of a compressor impeller. A throttle member is provided in the intake passage. The plurality of throttle members are arranged in the circumferential direction of the compressor wheel. The throttle member is driven by the actuator and projects radially inward of the intake passage to throttle the intake passage.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open publication No. 2016-173051

Disclosure of Invention

Problems to be solved by the invention

The air suction passage is throttled by the throttle member, thereby suppressing a decrease in heat insulation efficiency at a low flow rate. It is desired to develop a technique for further suppressing the decrease in the adiabatic efficiency when the intake passage is throttled in this manner.

The present disclosure aims to provide a centrifugal compressor and a supercharger capable of suppressing a decrease in adiabatic efficiency.

Means for solving the problems

In order to solve the above problem, a centrifugal compressor according to an aspect of the present disclosure includes: an impeller having a main body and a plurality of blades provided on an outer peripheral surface of the main body; an intake passage facing the impeller in the direction of the rotation axis; and a throttle mechanism which has a throttle member provided in the intake passage and in which a ratio calculated by dividing a distance between an outer peripheral end of a leading edge of the vane and the throttle member by a maximum protrusion height of the throttle member from an inner wall surface of the intake passage is 4 or less.

The throttle member may have an opposing surface that opposes the outer peripheral end in the axial direction of the impeller, and the opposing surface may be provided between a position in the axial direction of the outer peripheral end and a position in the axial direction of the inner peripheral end of the leading edge.

In order to solve the above problem, a supercharger according to an aspect of the present disclosure includes the centrifugal compressor.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, a decrease in heat insulation efficiency can be suppressed.

Drawings

Fig. 1 is a schematic sectional view of a supercharger.

Fig. 2 is an extracted view of a dotted line portion of fig. 1.

Fig. 3 is an exploded perspective view of components constituting the link mechanism.

Fig. 4 is a sectional view taken along line IV-IV of fig. 2.

Fig. 5 is a first diagram for explaining the operation of the link mechanism (throttle mechanism).

Fig. 6 is a second diagram for explaining the operation of the link mechanism.

Fig. 7 is a third diagram for explaining the operation of the link mechanism.

Fig. 8 is a drawing of a two-dot chain line portion of fig. 2.

Fig. 9 is a graph showing a relationship between a distance and an improvement rate of adiabatic efficiency.

Fig. 10 is a diagram for explaining a range of arrangement of the protruding portion of the first throttle member.

Fig. 11 is a graph showing the result of simulation of the flow of the peeled air based on the mathematical formula 1.

Detailed Description

An embodiment of the present disclosure will be described in detail below with reference to the drawings. Dimensions, materials, other specific numerical values, and the like shown in the embodiments are merely examples for easy understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description thereof is omitted. In addition, elements not directly related to the present disclosure are not shown.

Fig. 1 is a schematic sectional view of a supercharger TC. The direction of arrow L shown in fig. 1 is described as the left side of the supercharger TC. The direction of arrow R shown in fig. 1 is described as the right side of the supercharger TC. As shown in fig. 1, the supercharger TC includes a supercharger body 1. The supercharger body 1 includes a bearing housing 2. A turbine housing 4 is coupled to the left side of the bearing housing 2 by a fastening bolt 3. The compressor casing 100 is coupled to the right side of the bearing casing 2 by a fastening bolt 5.

The bearing housing 2 has a housing hole 2 a. The housing hole 2a penetrates in the left-right direction of the supercharger TC. The bearing 6 is provided in the housing hole 2 a. Fig. 1 shows a full-floating bearing as an example of the bearing 6. However, the bearing 6 may be another radial bearing such as a semi-floating bearing or a rolling bearing. The main shaft 7 is pivotally supported by a bearing 6 to be freely rotatable. A turbine wheel 8 is provided at the left end of the main shaft 7. The turbine wheel 8 is housed in the turbine housing 4 so as to be freely rotatable. A compressor impeller 9 (impeller) is provided at the right end of the main shaft 7.

The compressor wheel 9 has a main body portion 9 a. The outer peripheral surface 9b of the main body 9a faces one side in the direction of the rotation axis of the compressor impeller 9 (hereinafter simply referred to as the rotation axis direction; the axial direction of the main shaft 7, the left-right direction of the supercharger TC). The back surface 9c faces the other side in the rotation axis direction. On the outer circumferential surface 9b, a plurality of blades 9d are provided at intervals in the circumferential direction of the outer circumferential surface 9 b. The vanes 9d protrude from the outer peripheral surface 9b in the radial direction. The compressor impeller 9 is rotatably housed in the compressor casing 100. The compressor shell 100 has a first shell member 110 and a second shell member 120. The first case member 110 and the second case member 120 will be described in detail later.

The compressor casing 100 is formed with an inlet 10. The intake port 10 opens on the right side of the supercharger TC. The intake port 10 is connected to an air cleaner, not shown. The diffuser flow path 11 is formed in a state where the bearing housing 2 and the compressor housing 100 are coupled by the fastening bolt 5. The diffuser flow path 11 pressurizes air. The diffuser flow path 11 is formed in an annular shape from the inside in the radial direction (hereinafter simply referred to as the radial direction) of the main shaft 7 (compressor impeller 9) toward the outside. The diffuser flow path 11 is located radially inward and communicates with the inlet 10 via the compressor impeller 9.

Further, a compressor scroll passage 12 is formed inside the compressor casing 100. The compressor scroll passage 12 is annular. The compressor scroll flow path 12 is located radially outward of the compressor impeller 9. The compressor scroll passage 12 communicates with an intake port of an engine, not shown. The compressor scroll flow path 12 also communicates with the diffuser flow path 11. When the compressor impeller 9 rotates, air is sucked into the compressor casing 100 through the suction port 10. The sucked air is accelerated by the centrifugal force while flowing between the plurality of blades 9d of the compressor impeller 9. The air having undergone the speed increase is pressurized in the diffuser flow path 11 and the compressor scroll flow path 12. The air having been pressurized flows out from an unillustrated discharge port and is guided to an intake port of the engine.

In this way, the supercharger TC includes a centrifugal compressor C (compressor). The centrifugal compressor C includes: compressor casing 100, compressor impeller 9, and compressor scroll passage 12.

An exhaust port 13 is formed in the turbine shell 4. The exhaust port 13 opens on the left side of the supercharger TC. The exhaust port 13 is connected to an exhaust gas purification device not shown. The turbine casing 4 is provided with a flow passage 14 and a turbine scroll flow passage 15. The turbine scroll flow path 15 is located radially outward of the turbine wheel 8. The flow path 14 is located between the turbine wheel 8 and the turbine scroll flow path 15.

The turbine scroll passage 15 communicates with a gas inlet, not shown. Exhaust gas discharged from an exhaust manifold of an engine, not shown, is guided to the gas inlet port. The turbo scroll passage 15 also communicates with the passage 14 described above. The exhaust gas introduced from the gas inlet into the turbine scroll passage 15 is guided to the exhaust port 13 through the passage 14 and the inter-blade space of the turbine wheel 8. The exhaust gas introduced into the exhaust port 13 rotates the turbine wheel 8 during the circulation thereof.

The rotational force of the turbine wheel 8 is transmitted to the compressor wheel 9 via the main shaft 7. As described above, the air is boosted by the rotational force of the compressor impeller 9 and is guided to the intake port of the engine.

Fig. 2 is an extracted view of a dotted line portion of fig. 1. Fig. 2 shows the compressor impeller 9, the compressor casing 100, and a throttle member described later in a drawn manner. As shown in fig. 2, the first case member 110 of the compressor case 100 is located on the right side (the side away from the bearing case 2) in fig. 2 than the second case member 120.

The first case member 110 has a substantially cylindrical shape. The first case member 110 has a small diameter portion 110a, a medium diameter portion 110b, and a large diameter portion 110 c. The small diameter portion 110a is farthest from the bearing housing 2. The large diameter portion 110c is closest to the bearing housing 2. The middle diameter portion 110b is located between the small diameter portion 110a and the large diameter portion 110 c. The small diameter portion 110a has a smaller outer diameter than the medium diameter portion 110 b. The middle diameter portion 110b has a smaller outer diameter than the large diameter portion 110 c. However, the first case member 110 may not have the small diameter portion 110a, the middle diameter portion 110b, and the large diameter portion 110 c. For example, the outer diameter may be substantially constant in the direction of the axis of rotation.

The first case member 110 has a through hole 111 formed therein. The through hole 111 penetrates the first case member 110 in the rotation axis direction. The through hole 111 penetrates the small diameter portion 110a, the intermediate diameter portion 110b, and the large diameter portion 110c in the rotation axis direction. One end of the through hole 111 is the air inlet 10.

The through hole 111 has a parallel portion 111a and a reduced diameter portion 111 b. The parallel portion 111a is located on one end side of the through hole 111 with respect to the diameter-reduced portion 111 b. One end of the parallel portion 111a is the inlet 10. The inner diameter of the parallel portion 111a is substantially constant in the axial direction. One end of the reduced diameter portion 111b is continuous with the parallel portion 111 a. The inner diameter of one end of the reduced diameter portion 111b is substantially equal to the inner diameter of the parallel portion 111 a. The inner diameter of the reduced diameter portion 111b becomes smaller as it goes away from the parallel portion 111a (as it goes closer to the second case member 120).

A cutout portion 112a is formed in an outer peripheral portion of an end surface 112 of the first case member 110 on the second case member 120 side. The notch 112a is, for example, annular.

A receiving groove 112b is formed in an end surface 112 of the first case member 110. The receiving groove 112b is recessed toward the suction port 10 side (the side away from the second housing member 120) with respect to the end surface 112. The housing groove 112b is, for example, substantially annular when viewed in the axial direction. In other words, the housing groove 112b is recessed radially outward from the inner wall of the through hole 111.

A bearing hole 112d is formed in a wall surface 112c of the housing groove 112b on the suction port 10 side (the small diameter portion 110a side, the side away from the second case member 120). The bearing hole 112d extends from the wall surface 112c toward the inlet port 10 in parallel with the rotation axis direction. The two bearing holes 112d are provided at a distance in the rotation direction of the compressor impeller 9 (hereinafter simply referred to as the rotation direction). The two bearing holes 112d are arranged at positions shifted by 180 degrees in the rotational direction.

The second case member 120 has a through hole 121 formed therein. The through hole 121 penetrates the second case member 120 in the rotation axis direction. The inner diameter of the end portion of the through hole 121 on the first case member 110 side is substantially equal to the inner diameter of the end portion of the through hole 111 on the second case member 120 side. A shield portion 121a is formed at an inner wall of the through hole 121 in the second case member 120. Shroud portion 121a faces compressor wheel 9 from the radially outer side. The inner diameter of the shield portion 121a increases as it goes away from the first case member 110. An end portion of the shroud portion 121a on the opposite side from the first case member 110 communicates with the diffuser flow path 11 described above.

A receiving groove 122a is formed in an end surface 122 of the second case member 120 on the first case member 110 side. The housing groove 122a is recessed toward the diffuser flow path 11 side (the side away from the first casing member 110) with respect to the end surface 122. The accommodation groove 122a is, for example, substantially annular when viewed from the axial direction. In other words, the housing groove 122a is recessed radially outward from the inner wall of the through hole 121. The large diameter portion 110c is inserted into the accommodation groove 122 a. The end surface 112 of the first case member 110 abuts against the wall surface of the housing groove 122a on the diffuser flow path 11 side.

The suction passage 130 is formed by the through-hole 111 of the first case member 110 and the through-hole 121 of the second case member 120. The intake passage 130 communicates the intake port 10 with the diffuser flow path 11. The compressor wheel 9 is provided in the intake passage 130. The cross-sectional shape of the intake passage 130 (through holes 111 and 121) perpendicular to the rotation axis direction is, for example, a circular shape centered on the rotation axis of the compressor impeller 9. However, the cross-sectional shape of the air intake passage 130 is not limited thereto. Further, a seal member, not shown, is disposed in the cutout portion 112a of the first case member 110. The flow rate of air circulating in the gap between the first case member 110 and the second case member 120 can be suppressed by the sealing member. However, the cut-out portion 112a and the sealing member are not necessarily configured.

Fig. 3 is an exploded perspective view of components constituting the link mechanism 200 (throttle mechanism). In fig. 3, only the first shell member 110 in the compressor shell 100 is shown. As shown in fig. 3, the link mechanism 200 includes: the compressor casing 100, the first throttle member 210 (throttle member), the second throttle member 220 (throttle member), the coupling member 230, and the rod portion 240.

The first throttling part 210 has a bent portion 211. The curved portion 211 has a substantially semicircular arc shape. One end surface 211a and the other end surface 211b in the rotational direction in the bent portion 211 extend in parallel with the radial direction and the rotational axis direction. However, the one end surface 211a and the other end surface 211b may be inclined with respect to the radial direction and the rotational axis direction.

An arm portion 212 is provided on the one end surface 211a side of the bent portion 211. The arm portion 212 extends radially outward from the outer peripheral surface 211c of the bent portion 211. The arm portion 212 extends in a direction inclined with respect to the radial direction (toward the second orifice member 220 side).

The second throttling part 220 has a bent portion 221. The curved portion 221 has a substantially semicircular arc shape. One end surface 221a and the other end surface 221b in the rotational direction in the bent portion 221 extend parallel to the radial direction and the rotational axis direction. However, the one end surface 221a and the other end surface 221b may be inclined with respect to the radial direction and the rotational axis direction.

An arm 222 is provided on one end surface 221a side of the bent portion 221. The arm portion 222 extends radially outward from the outer peripheral surface 221c of the bent portion 221. The arm portion 222 extends in a direction inclined with respect to the radial direction (toward the first orifice member 210 side).

The curved portion 211 and the curved portion 221 face each other with the rotation center (the intake passage 130) of the compressor impeller 9 interposed therebetween. One end surface 211a of the curved portion 211 and the other end surface 221b of the curved portion 221 face each other. The other end surface 211b of the curved portion 211 faces one end surface 221a of the curved portion 221.

The connecting member 230 is located closer to the intake port 10 than the first throttle member 210 and the second throttle member 220. The coupling member 230 has a substantially circular arc shape. The coupling member 230 has bearing

holes

231 and 232 formed on one end side and the other end side in the rotation direction. The bearing holes 231 and 232 open in an end surface 233 of the coupling member 230 on the side of the first throttle member 210 and the second throttle member 220. The bearing holes 231, 232 extend in the rotation axis direction. Here, the bearing holes 231 and 232 are formed by non-penetrating holes. However, the bearing holes 231 and 232 may penetrate the coupling member 230 in the rotation axis direction.

A rod connecting portion 234 is provided between the bearing holes 231, 232 in the coupling member 230. The rod connecting portion 234 is provided on an end surface 235 of the coupling member 230 on the side opposite to the first and

second orifice members

210 and 220. The rod connecting portion 234 protrudes from the end surface 235 in the rotation axis direction. The rod connecting portion 234 has a substantially cylindrical shape, for example.

The shaft portion 240 has a generally cylindrical shape. A flat surface portion 241 is formed at one end of the rod portion 240. The planar portion 241 extends substantially in a plane direction perpendicular to the rotation axis direction. The plane portion 241 has a bearing hole 242. The bearing hole 242 extends in the rotation axis direction. A coupling portion 243 is provided at the other end of the rod portion 240. The coupling portion 243 has a coupling hole 243 a. The coupling portion 243 is coupled to an actuator described later. The bearing hole 242 may be, for example, an elongated hole that is longer in the axial direction of the lever portion 240 than in the direction perpendicular to the rotational axis direction and the axial direction of the lever portion 240 (the left-right direction in fig. 5 described later).

A rod large-diameter portion 244 is formed between the flat surface portion 241 and the coupling portion 243 in the rod 240. The outer diameter of the rod large-diameter portion 244 is larger than a portion of the rod 240 that is continuous with the flat surface portion 241 side and the coupling portion 243 side with respect to the rod large-diameter portion 244.

An insertion hole 113 is formed in the first case member 110. One end 113a of the insertion hole 113 opens to the outside of the first case member 110. The insertion hole 113 extends in a plane direction perpendicular to the rotation axis direction, for example. The insertion hole 113 is located radially outward of the through hole 111 (intake passage 130). The rod 240 is inserted into the insertion hole 113 on the side of the flat portion 241. The rod large-diameter portion 244 is guided by the inner wall surface of the insertion hole 113 of the first case member 110. Therefore, the rod portion 240 restricts movement of the insertion hole 113 in the axial direction other than the central axis direction (the central axis direction of the rod portion 240).

A receiving hole 114 is formed in the first case member 110. The housing hole 114 is opened in the wall surface 112c of the housing groove 112 b. The housing hole 114 is recessed from the wall surface 112c toward the suction port 10 (a side away from the second housing member 120). The housing hole 114 has a substantially circular arc shape when viewed from the rotation axis direction. The housing hole 114 extends on the wall surface 112c to be longer in the rotational direction than the coupling member 230. The receiving hole 114 is spaced apart from the bearing holes 231 and 232 in the rotation axis direction. The receiving hole 114 is located closer to the second case member 120 side (the first throttle member 210 side) than the insertion hole 113.

A communication hole 115 is formed in the first case member 110. The communication hole 115 communicates the insertion hole 113 with the accommodation hole 114. The communication hole 115 is formed in the substantially middle portion in the rotational direction in the housing hole 114. The communication hole 115 extends substantially parallel to the extending direction of the insertion hole 113. The width of the through hole 115 in the plane direction perpendicular to the extending direction and the rotation axis direction of the insertion hole 113 is larger than the outer diameter of the rod connecting portion 234 of the coupling member 230. The communication hole 115 is an elongated hole satisfying the following conditions: the width of the insertion hole 113 in the extending direction is larger than the width of the insertion hole 113 in the plane direction perpendicular to the extending direction and the rotation axis direction.

The connecting member 230 is received in the receiving hole 114. The receiving hole 114 has a longer length in the rotational direction and a larger width in the radial direction than the coupling member 230. Therefore, the coupling member 230 is allowed to move in the plane direction perpendicular to the rotation axis direction inside the housing hole 114.

The rod connecting portion 234 is inserted through the insertion hole 113 from the communication hole 115. The bearing hole 242 of the rod portion 240 inserted through the insertion hole 113 is opposed to the communication hole 115. The rod connecting portion 234 is inserted (connected) into the bearing hole 242. The lever connecting portion 234 is pivotally supported by the bearing hole 242.

Fig. 4 is a sectional view taken along line IV-IV of fig. 2. As shown by a broken line in fig. 4, the first throttle member 210 has a coupling shaft 213 and a rotation shaft 214. The coupling shaft portion 213 and the rotation shaft portion 214 protrude from the end surface of the first throttle member 210 on the inlet port 10 side (the wall surface 112c side of the housing groove 112 b) in the rotation axis direction. The coupling shaft 213 and the rotation shaft 214 extend toward the depth side of the drawing sheet in fig. 4. The rotation shaft 214 extends parallel to the connection shaft 213.

The outer diameter of the coupling shaft 213 is smaller than the inner diameter of the bearing hole 231 of the coupling member 230. The coupling shaft 213 is inserted through the bearing hole 231. The coupling shaft 213 is pivotally supported by the bearing hole 231. The outer diameter of the rotation shaft part 214 is smaller than the inner diameter of the bearing hole 112d of the first case member 110. The rotation shaft 214 is inserted through one of the bearing holes 112 d. The rotation shaft 214 is pivotally supported by the bearing hole 112d (see fig. 2). That is, the rotation shaft 214 connects the first throttle member 210 to the wall surface 112c, and the wall surface 112c faces the first throttle member 210 in the rotation shaft direction.

The second orifice member 220 has a coupling shaft 223 and a rotating shaft 224. The connecting shaft 223 and the rotating shaft 224 protrude from the end surface of the second throttle member 220 on the inlet port 10 side (the wall surface 112c side of the housing groove 112 b) in the rotating shaft direction. The coupling shaft 223 and the rotation shaft 224 extend toward the depth side of the drawing in fig. 4. The rotation shaft 224 extends parallel to the connection shaft 223.

The outer diameter of the coupling shaft portion 223 is smaller than the inner diameter of the bearing hole 232 of the coupling member 230. The coupling shaft 223 is inserted through the bearing hole 232. The coupling shaft portion 223 is pivotally supported by the bearing hole 232. The outer diameter of the rotation shaft 224 is smaller than the inner diameter of the bearing hole 112 d. The rotation shaft 224 is inserted into the other bearing hole 112 d. The rotation shaft 224 is pivotally supported by the bearing hole 112d (see fig. 2). That is, the rotating shaft 224 connects the second orifice member 220 to the wall surface 112c, and the wall surface 112c faces the second orifice member 220 in the rotating shaft direction.

Thus, the link mechanism 200 is constituted by a four-joint link mechanism. The four links (joints) are a first throttle member 210, a second throttle member 220, a first case member 110, and a coupling member 230. Since the link mechanism 200 is constituted by a four-joint link mechanism, it is a single degree of freedom and is easy to control while being interlocked in a limited manner.

Fig. 5 is a first diagram for explaining the operation of the link mechanism 200. Fig. 5, 6, and 7 show views seen from the inlet 10 side. As shown in fig. 5, one end of the drive spindle 251 of the actuator 250 is coupled to the coupling portion 243 of the rod portion 240.

In the configuration shown in fig. 5, the first and

second throttling members

210, 220 abut each other. At this time, as shown in fig. 2 and 4, the radially inner portion of the first throttle member 210, i.e., the projection 215, projects into the intake passage 130. The second throttle member 220 has a radially inner portion, i.e., a protrusion 225, that protrudes into the intake passage 130. The positions of the first and

second throttle members

210 and 220 at this time are referred to as throttle positions.

In the throttle position, the rotational direction ends 215a, 215b of the projection 215 abut the rotational direction ends 225a, 225b of the projection 225. An annular aperture 260 is formed by the projection 215 and the projection 225. The inner diameter of the annular hole 260 is smaller than the inner diameter of the portion of the intake passage 130 from which the protruding

portions

215 and 225 protrude. The inner diameter of the annular hole 260 is smaller than the inner diameter of any portion of the suction passage 130, for example.

Fig. 6 is a second diagram for explaining the operation of the link mechanism 200. Fig. 7 is a third diagram for explaining the operation of the link mechanism 200. The actuator 250 linearly moves the rod portion 240 in a direction (vertical direction in fig. 6 and 7) intersecting the rotation axis direction. The rod portion 240 moves upward from the state shown in fig. 5. In the arrangement of fig. 7, the lever portion 240 is moved by a larger amount with respect to the arrangement of fig. 5, as compared to the arrangement of fig. 6.

When the lever portion 240 moves, the coupling member 230 also moves upward via the lever portion connecting portion 234 as shown in fig. 6 and 7. At this time, the coupling member 230 allows rotation about the lever connecting portion 234 as a rotation center. In addition, the inner diameter of the bearing bore 242 of the rod portion 240 has a slight play with respect to the outer diameter of the rod portion connecting portion 234. Therefore, the coupling member 230 allows slight movement in the plane direction perpendicular to the rotation axis direction.

As described above, the link mechanism 200 is a four-joint link mechanism, and the coupling member 230, the first throttle member 210 and the second throttle member 220 show a state of single degree of freedom with respect to the first case member 110. Specifically, the coupling member 230 slightly rotates counterclockwise and slightly swings in the left-right direction within the above-described allowable range as shown in fig. 6 and 7.

In the first throttle member 210, the rotation shaft portion 214 is pivotally supported by the first case member 110, and therefore movement in the plane direction perpendicular to the rotation shaft direction is restricted. The coupling shaft 213 is pivotally supported by the coupling member 230. Since the coupling member 230 is provided to allow movement, the coupling shaft 213 can move in a plane direction perpendicular to the rotation axis direction. As a result, the first throttle member 210 rotates clockwise as shown in fig. 6 and 7 around the rotation shaft 214 as the rotation center with the movement of the coupling member 230.

Similarly, in the second throttle member 220, the rotation shaft 224 is pivotally supported by the first case member 110, and therefore, movement in the plane direction perpendicular to the rotation shaft direction is restricted. The coupling shaft 223 is pivotally supported by the coupling member 230. Since the coupling member 230 is provided to allow movement, the coupling shaft 223 can move in a plane direction perpendicular to the rotation axis direction. As a result, the second orifice member 220 rotates clockwise about the rotation shaft 224 as shown in fig. 6 and 7 as the coupling member 230 moves.

Thus, the first throttling part 210 and the second throttling part 220 move in the direction of being spaced apart from each other in the order of fig. 6 and 7. The

projections

215 and 225 move outward in the radial direction with respect to the throttle position (retracted position). In the retracted position, for example, the

protrusions

215 and 225 are flush with the inner wall surface of the intake passage 130 or are located radially outward of the inner wall surface of the intake passage 130. When moving from the retracted position to the throttle position, the first throttle member 210 and the second throttle member 220 come close to and abut each other in the order of fig. 7, 6, and 5. In this way, the first and

second throttling members

210, 220 are switched between the throttling position and the retracted position according to the rotation angle about the

rotation shaft portions

214, 224.

Fig. 8 is a drawing of a two-dot chain line portion of fig. 2. Although the first throttle member 210 side is described below as an example, the second throttle member 220 also has the same configuration (arrangement) as the first throttle member 210. In fig. 8, the first throttling part 210 is in the throttling position. In the throttle position, the protrusion 215 of the first throttle member 210 and the protrusion 225 of the second throttle member 220 protrude radially inward in the intake passage 130.

The protruding portion 215 of the first throttle member 210 has an opposed surface 215 c. The opposed surface 215c is opposed to the leading edge LE of the vane 9d of the compressor wheel 9. The leading edge LE is the upstream end in the flow direction of the air in the vane 9 d. Here, the leading edge LE is inclined with respect to the radial direction. The leading edge LE approaches the radially outer side and approaches the left side shown in fig. 8 (the side away from the intake port 10, the side of the bearing 6). However, the leading edge LE may be parallel with respect to the radial direction.

The outer peripheral end 9e of the front edge LE is the radially outermost portion of the front edge LE. Here, the outer peripheral end 9e is located most to the left side in fig. 8 (the side away from the intake port 10, the side of the bearing 6) in the leading edge LE.

The inner peripheral end 9f of the leading edge LE is the radially innermost portion of the leading edge LE. Here, the inner peripheral end 9f is located most to the right side in fig. 8 (the suction port 10 side, the side away from the bearing 6) in the leading edge LE.

The axial position of the outer peripheral end 9e is located leftward in fig. 8 with respect to the facing surface 215c of the projection 215. The axial position of the inner peripheral end 9f is located more rightward in fig. 8 than the facing surface 215c of the projection 215. That is, the facing surface 215c is provided between the axial position of the outer peripheral end 9e of the leading edge LE and the axial position of the inner peripheral end 9f of the leading edge LE. Thus, even when the front edge LE has a shape inclined with respect to the direction perpendicular to the axial direction, the outer peripheral end 9e can be brought close to the protruding portion 215.

As shown in fig. 8, the distance (shortest distance, axial distance) between the facing surface 215c of the projection 215 of the first throttle member 210 and the outer peripheral end 9e of the leading edge LE is set to a distance LL. The maximum protrusion height (height at the throttle position) of the protrusion 215 protruding from the inner wall surface of the intake passage 130 is set to the height h_max。

Fig. 9 is a graph showing a relationship between the distance LL and the improvement rate of the adiabatic efficiency. In fig. 9, the vertical axis represents the above-described distance LL. The horizontal axis represents the improvement rate of adiabatic efficiency. Here, the improvement rate of the adiabatic efficiency means a rate at which the adiabatic efficiency is improved (increased) by moving the first and

second throttling members

210 and 220 to the throttling position with respect to the fully open position. In the fully open position, the protruding portion 215 of the first throttle member 210 and the protruding portion 225 of the second throttle member 220 are positioned radially outward (radially outward of the intake passage 130, for example).

In fig. 9, legends AA, AB, and AC differ from each other in the compression ratio of air. The compression ratio is lowest for legend AA and highest for legend AC. As shown in fig. 9, the smaller the distance LL at each compression ratio, the higher the improvement rate of the adiabatic efficiency. That is, the improvement rate of the adiabatic efficiency increases as the first throttling part 210 approaches the leading edge LE.

Fig. 10 is a diagram for explaining a range of arrangement of the protrusion 215 of the first throttle member 210. Fig. 10 is a view of fig. 8, which is turned upside down and left-right, for easy understanding of the correspondence relationship with fig. 11. The air throttled by the protrusion 215 and separated from the inner wall surface of the intake passage 130 slightly gradually spreads radially outward as indicated by an arrow FL in fig. 10 and flows in the rotation axis direction. It is known that the following relation of equation 1 is established in the flow of the air to be separated at this time. Here, the distance X represents the distance between the facing surface 215c of the protruding portion 215 and the position where the peeled air reattaches to the inner wall surface of the air intake passage 130. Re represents the Reynolds number.

[ formula 1]

Fig. 11 is a graph showing the result of simulation of the flow of the peeled air based on the mathematical formula 1. In fig. 11, the horizontal axis represents the height h of the protrusion 215 obtained by dividing the distance x toward the downstream side with the facing surface 215c set to 0_maxAnd the calculated ratio (hereinafter referred to as x ratio). The vertical axis represents the distance r from the inner wall surface of the intake passage 130 to the inside in the radial direction divided by the height h of the protrusion 215_maxAnd the calculated ratio.

Legends BA, BB, BC differ from each other in the flow rate of air. Legend BA has the highest flow rate and legend BC has the lowest flow rate. As shown in FIG. 11In each flow velocity, when the x ratio exceeds 4, the air rapidly spreads radially outward and flows. On the contrary, in the range where the x ratio is 4 or less, the height h of the protrusion 215 is only set_maxThe range of 10% or less, the air expands radially outward.

Therefore, in the link mechanism 200, as shown in fig. 10, the distance LL between the facing surface 215c of the projecting portion 215 of the first throttling member 210 and the outer peripheral end 9e of the front edge LE is set to the height h of the projecting portion 215_maxThe first throttle member 210 is disposed at a position 4 times or less. That is, the front edge LE is located in the range where the x ratio is 4 or less with respect to the facing surface 215c of the projection 215.

As a result, the air passing through the projection 215 reaches the leading edge LE while hardly spreading radially outward. That is, the compressor impeller 9 can perform compression while the throttling effect by the first throttling member 210 is sufficiently retained. In addition, since the protrusion 215 and the leading edge LE have the positional relationship described above, the flow velocity from the radially inner side of the leading edge LE to the vicinity of the intermediate position is increased and the inflow angle is made good. This makes it possible to supplement the amount of work of the compressor impeller 9 that cannot be obtained near the shroud portion 121a with the amount of work from the radially inner side of the leading edge LE to the vicinity of the intermediate position.

Although an embodiment of the present disclosure has been described above with reference to the drawings, the present disclosure is not limited to the embodiment. Various modifications and alterations can be made by those skilled in the art within the scope of the claims, and these modifications and alterations also fall within the technical scope of the present disclosure.

For example, in the above-described embodiment, the case where the first throttle member 210 and the second throttle member 220 are included as the throttle members has been described. However, at least one of the first and

second throttling members

210 and 220 may be provided. Further, three or more throttling members may be provided.

The link mechanism 200 described in the above embodiment is merely an example of the throttle mechanism. The throttle mechanism may be any mechanism as long as it can move to the throttle position and the retreat position (fully open position) by changing the radial position of the throttle member.

In the above embodiment, the facing surface 215c is provided between the position in the axial direction of the outer peripheral end 9e of the leading edge LE and the position in the axial direction of the inner peripheral end 9f of the leading edge LE. In other words, the outer peripheral end 9e and the inner peripheral end 9f are located on opposite sides in the axial direction with respect to the facing surface 215 c. However, the inner peripheral end 9f may be located on an extension of the facing surface 215c in the radial direction. The inner end 9f may be located closer to the outer end 9e than the opposite surface 215 c.

Industrial applicability of the invention

The present disclosure is applicable to centrifugal compressors and superchargers.

Description of the symbols

9: a compressor impeller (impeller); 9 a: a main body portion; 9 b: an outer peripheral surface; 9 d: a blade; 9 e: an outer peripheral end; 9 f: an inner peripheral end; 130: an air intake passage; 200: a link mechanism (throttle mechanism); 210: a first throttle member (throttle member); 215 c: opposite surfaces; 220: a second throttle member (throttle member); c: a centrifugal compressor; LE: a leading edge; LL: a distance; TC: a supercharger.

Claims

1. A centrifugal compressor is characterized by comprising:

an impeller having a main body and a plurality of blades provided on an outer peripheral surface of the main body;

an intake passage facing the impeller in a rotation axis direction;

and a throttle mechanism that has a throttle member provided in the intake passage, and a ratio calculated by dividing a distance between an outer peripheral end of a leading edge of the vane and the throttle member by a maximum protrusion height of the throttle member from an inner wall surface of the intake passage is 4 or less.

2. The centrifugal compressor according to claim 1,

the throttle member has an opposed surface opposed to the outer peripheral end in an axial direction of the impeller,

the facing surface is provided between the axial position of the outer peripheral end and the axial position of the inner peripheral end of the leading edge.

3. A supercharger is characterized in that the supercharger is provided with a supercharger body,

the centrifugal compressor according to claim 1 or 2 is provided.